More than a dozen arrested, $6.5m worth of cannabis seized in Rotorua operation

More than a dozen people have been arrested and $6.5 million worth of cannabis removed from the black market after a six month police operation.

Detective Inspector Lindsay Pilbrow, Bay of Plenty Field Crime Manager said the significant operation shut down 14 grow houses in Rotorua.

The operation was a joint investigation between Police and Immigration New Zealand officers from the Ministry of Business, Innovation and Employment (MBIE).

It was targeting residential rental properties being used to house large-scale commercial cannabis growing operations involving Vietnamese organised crime groups.

Of the 16 Vietnamese nationals arrested, 14 were facing charges related to the cannabis growing setup and other associated offences. Two were arrested in relation to Immigration Act Offences.

Five residential properties, 21 bank accounts and two vehicles were also been restrained.

As well as cannabis, tens of thousands of dollars of cash were seized, along with cannabis growing equipment.

Police had searched 21 residential properties searched across Rotorua and found 14 had "active and significant" cannabis growing operations. Ten of the houses were rental properties located in residential areas.

"This was a well organised, significant and well-resourced grow operation with all the properties were linked to the same criminal network. Police believe the drugs were destined for sale to other organised criminal groups to on sell," Pilbrow said.

"Over 3500 high value plants were seized along with 97 pounds of dried cannabis head packaged and ready for the wholesale market

"The cannabis seized has a bulk sale value of $1.8 million, but has a potential street market value well in excess of $6.5 million depending on how it is sold."

Police were also alleging all the houses had been using stolen power illegally diverted by the offenders from nearby power boxes, estimating $30,000 worth of power had been diverted per week to run the grow houses.

"The scale of this operation is one I've not seen before. It is a multimillion-dollar business used to fund other organised criminal activities. We believe the equipment located and seized at the grow houses is worth more than $1 million alone," Pilbrow said.

"Many of these houses were packed to the brim with cannabis plants at various stages of growth. Houses had been altered to allow maximum use of space, with specialised timing and ventilation systems fitted to assist in the growing and to also avoid detection.

Pilbrow said this would be a "significant blow" to those involved in the drug operation.

"These organised criminal groups have embedded themselves within communities simply to cause harm. Not only does the drug use put people at harm, but the associated offending such as the theft of electricity is a significant risk to households and members of the public."

More than 220 staff from across Bay of Plenty, Waikato and Auckland districts were involved, as well as support from electrical companies to make the properties safe and assist with the investigation phase.

The operation is still ongoing, and police say more search activity is planned in Auckland and the Bay of Plenty with further arrests and charges have not been ruled out.

Police said they continue to see an increase in rental properties in suburban areas being converted into large-scale cannabis growing operations funded and controlled by organised criminal groups.

Police said illegal drugs cause significant harm to individuals, families and communities and police encourage anyone with information about drug-related offending to come forward by calling 111 if it is happening now, or report information after the fact via 105.

Landlords urged to be 'vigilant'

Police are also encouraging landlords and property managers to be vigilant and look out for signs that a property may be being used for illegal drug cultivation. They said this activity can cause significant damage, pose a fire risk and may jeopardise insurance payouts.

"Landlords need to remember they have obligations to carry out due diligence on prospective tenants."

Police recommend landlords to carry out checks before signing up tenants including carrying out reference checks, meet tenants face-to-face, check IDs and credit and income verifications.

"Always ensure you carry out regular inspections of your properties. If tenants have a preference to pay rent in cash or offer to pay more to avoid inspections, that should be a red flag."

They said other warning signs can include blacked-out or permanently covered windows, extractor fans, ventilation systems or unauthorised structural changes to the exterior of the property or signs that an electricity meter has been tampered with or bypassed.

Police encouraged people to report anything suspicions to via 105 or Crime Stoppers anonymously on 0800 555 111.